Found out the problem, as as expected it was user error on my part.
When I reset my password, I used some special characters in it.
Turns out that ASC doesn't like that, even though it works fine on their website.
So I reset my password again to one that doesn't contain any special characters & it's working now.
So a mistake on my part, but also an error on Arturias' part as ASC should accept the same password that their own website does.
Some people, like myslef, use special characters to add another level of security.
Not supporting this in ASC is a bit behind-the-times.